Low-Dimensional Compounds Containing Bioactive Ligands. Part XX: Crystal Structures, Cytotoxic, Antimicrobial Activities and DNA/BSA Binding of Oligonuclear Zinc Complexes with Halogen Derivatives of 8-Hydroxyquinoline

Two tetranuclear [Zn4Cl2(ClQ)6]·2DMF (1) and [Zn4Cl2(ClQ)6(H2O)2]·4DMF (2), as well as three dinuclear [Zn2(ClQ)3(HClQ)3]I3 (3), [Zn2(dClQ)2(H2O)6(SO4)] (4) and [Zn2(dBrQ)2(H2O)6(SO4)] (5), complexes (HClQ = 5-chloro-8-hydroxyquinoline, HdClQ = 5,7-dichloro-8-hydroxyquinoline and HdBrQ = 5,7-dibromo-8-hydroxyquinoline) were prepared as possible anticancer or antimicrobial agents and characterized by IR spectroscopy, elemental analysis and single crystal X-ray structure analysis. The stability of the complexes in solution was verified by NMR spectroscopy. Antiproliferative activity and selectivity of the prepared complexes were studied using in vitro MTT assay against the HeLa, A549, MCF-7, MDA-MB-231, HCT116 and Caco-2 cancer cell lines and on the Cos-7 non-cancerous cell line. The most sensitive to the tested complexes was Caco-2 cell line. Among the tested complexes, complex 3 showed the highest cytotoxicity against all cell lines. Unfortunately, all complexes showed only poor selectivity to normal cells, except for complex 5, which showed a certain level of selectivity. Antibacterial potential was observed for complex 5 only. Moreover, the DNA/BSA binding potential of complexes 1–3 was investigated by UV-vis and fluorescence spectroscopic methods.

A Highly Sensitive Graphene-based Field Effect Transistor for the Detection of Myoglobin

Biomedical applications adapt Nano technology-based transistors as a key component in the biosensors for diagnosing life threatening diseases like Covid-19, Acute myocardial infarction (AMI), etc. The proposed work introduces a new biosensor, based on Graphene Field Effect Transistor (GFET), which is used in the diagnosis of Myoglobin (Mb) in human blood. Graphene-based biosensors are faster, more precise, stronger, and more trustworthy. A GFET is created in this study for the detection of myoglobin biomarker at various low concentrations. Because graphene is sensitive to a variety of biomarker materials, it can be employed as a gate material. When constructed Graphene FET is applied to myoglobin antigens, it has a significant response. The detection level for myoglobin is roughly 30 fg/ml, which is quite high. The electrical behavior of the GFET-based biosensor in detecting myoglobin marker is ideal for Lab-on-Chip platforms and Cardiac Point-of-Care Diagnosis.

A Novel RFET Sensor for Label-Free Biomolecule Detection

In the current scenario, COVID-19 has created a havoc negative impact on the lives of the people, which have triggered the research interest on the design and development of sensitive, low cost and power-efficient sensors for detecting a wide variety of biomolecules. Here, a novel hetero dielectric (HD) hetero material (HM) Bio-RFET based sensor is proposed which works as n or p MOSFET and n or p TFET and hence, is capable to sense the biomolecules through label-free dielectric modulation technique. Without labelling expenses, this biosensor detects a number of biomolecules present in human body as and when kept in a nano cavity. The dielectric polarization within the nanocavity due to the presence of foreign biomolecules under the influence of an electric field causes a variation in drain current. In this paper (SiO2 + TiO2) and AlGaAs/Si based HD-HM-RFET is explored for biosensing applications and mole fraction optimization of AlGaAs is done to obtain better results for four FETs. Work function of 4.5 eV is used in over drain and source electrodes, while metal work function of 4.7 eV  is used for gate electrode. Finally, we found that the proposed device possesses better sensing capability for varying dielectric constant (K = 20 to 80) and charge (−5 × 1011 to 1 × 1013 C/cm2) as compared to a (SiO2 + HfO2)-HM-RFET and Si based (SiO2 + TiO2)-RFET. Further, it is observed that n-(SiO2 + TiO2)-HM-TFET is the best among all FETs and has highest Id-Vgs sensitivity = 5.09 × 1013, ION/IOFF = 1.23 × 109, lowest SS = 20.3 mV/dec and Vth = 1.48 V.

Harry Potter Themed Digital Escape Room for Addressing Misconceptions in Stoichiometry

Chemistry is often seen as an and content-heavy subject. Many students struggle with chemistry because they attempt to memorize the content without understanding the concepts. As a result, students often have misconceptions. COVID-19 has driven teaching and learning online, and an escape room teaching method, which is a way to enhance student engagement, has gained popularity among educators in higher education. This study examines the effectiveness of teaching through a digital escape room as compared to a typical online lesson with a collaborative learning method to address misconceptions in stoichiometry. A Harry Potter themed digital escape room is created to spark the students' interest in chemistry and address misconceptions. Thirty-eight students from the Nanyang Polytechnic Foundation Program participated in this study. The students completed a pretest, a post-test, and a survey, in addition to participating in the digital escape room and a typical online lesson. Four topics were covered in this study: balancing chemical equations, calculating empirical formulas, identifying the type of chemical bonding, and interpreting element symbols. Out of these four topics, it was discovered that students tended to have difficulty calculating empirical formulas. It was found that, on average, students showed a 10% improvement in test scores after being taught through the digital escape room. This result is similar to results obtained from a typical online lesson with a collaborative learning method (9% improvement). This implies that a digital escape room is equally as effective as a typical online lesson with a collaborative learning method at addressing misconceptions. Teaching through a digital escape room has shown potential additional benefits of enhancing soft skills, promoting teamwork, the ability to work under time pressure, communication skills, innovation competency, and increasing student motivation. The researcher recommends the use of a digital escape room to complement typical lessons for these additional benefits.

In Situ Infrared Spectroscopy of NOx Reduction Catalysts: A Laboratory Exercise for In-Person and Virtual Learning

Infrared (IR) spectroscopy and catalysis represent two of the most practically relevant topics in chemistry, but they are normally taught in separate contexts at the undergraduate level. Although IR spectroscopy is introduced to students as a tool for organic compound characterization, it also finds wide applicability in the investigation of catalytic reactions. Here we present a laboratory exercise that binds the concepts of IR spectroscopy and catalysis together in the study of nitrogen oxide abatement by selective catalytic reduction-a reaction that is of industrial relevance and environmental importance. We originally designed the practical course for in-person instruction, but we adapted it into a virtual learning experience during the COVID-19 pandemic. Our analysis revealed that there was no significant difference between the performance of the in-person and virtual participants, suggesting that the online offering of the course could be a viable alternative to face-to-face instruction in case of extraordinary circumstances.

Functionalization of Porphyrins Using Metal-Catalyzed C–H Activation

The review is devoted to the C–H functionalization of porphyrins. Porphyrins exhibit the properties of organic semiconductors, light energy converters, chemical and electrochemical catalysts, and photocatalysts. The review describes the iridium- and palladium-catalyzed direct functionalization of porphyrins, with more attention given to the results obtained in our laboratory. The development and improvement of synthetic methods that do not require preliminary modification of the substrate with various functional groups are extremely important for the preparation of new organic materials based on porphyrins. This makes it possible to simplify the synthetic procedure, to make the synthesis more economical, environmentally safe, and simple to perform.

Research on the Teaching Reform of Inorganic Chemistry Based on SPOC and FCM during COVID-19

The COVID-19 pandemic has created a fundamental shift in the Chinese education system, which has compelled teachers and students to accommodate the process of online learning in a short period of time. Accompanied by the advancement of information technology and the emergence of small private online courses (SPOCs), a variety of online programs containing a wealth of new materials and novel pedagogical approaches have emerged. However, there is a lack of awareness among researchers about the efficacy of utilizing shared SPOCs in teaching at conventional universities. Flipped classroom model (FCM) can make up for this defect. This study aims to investigate the effectiveness of flipped learning on the basis of SPOC and to suggest explicit criteria for its reuse in conventional college education. We carried out a quasi-experiment in a course on inorganic chemistry and examined findings with regard to the engagement and performance of the learners. We also conducted a post-task questionnaire and interviews to examine the experiences of the students so that those experiences could be incorporated into the design and study plan for flipped learning based on SPOCs. It was shown that the average performance of students in the flipped SPOC-based classroom was superior to that of students in the traditional classroom. Furthermore, the combination of quantitative and qualitative data showed that the majority of students experienced the flipped classroom favorably regarding student interaction, accessible learning resources, and proactive academic outcomes.

Synthesis, structural analysis, and docking studies with SARS-CoV-2 of a trinuclear zinc complex with N-phenylanthranilic acid ligands.

The structure of a trinuclear zinc complex, hexakis(µ2-2-anilinobenzoato)diaquatrizinc(II), [Zn2(C13H10NO2)6(H2O)2] or (NPA)6Zn3(H2O)2 (NPA is 2-anilinobenzoate or N-phenylanthranilate), is reported. The complex crystallizes in the triclinic space group P-1 and the central ZnII atom is located on an inversion center. The NPA ligand is found to coordinate via the carboxylate O atoms with unique C-O bond lengths that support an unequal distribution of resonance over the carboxylate fragment. The axial H2O ligands form hydrogen bonds with neighboring molecules that stabilize the supramolecular system in rigid straight chains, with an angle of 180° along the c axis. π stacking is the primary stabilization along the a and b axes, resulting in a highly ordered supramolecular structure. Docking studies show that this unique supramolecular structure of a trinuclear zinc complex has potential for binding to the main protease (Mpro) in SARS-CoV-2 in a different location from Remdesivir, but with a similar binding strength.

Prototype of a Transition Metal Visualization App for the Learning of Stereochemistry in a General Chemistry Course: Initial Findings and Reflections

As part of COVID-19 preparedness, a student-developed, Android-based app was used as a pre-laboratory learning aid for a molecular modeling laboratory in a first-year general chemistry course. A worksheet activity with trigger codes and questions related to spatial features of transition metal complexes was designed. Using the Transition Metal Visualization (TMVis) app, learners activated augmented reality models on their mobile phones. Actual models were then constructed in class. Mean stereochemistry post-laboratory grades increased with stronger worksheet grades, though differences between worksheet grades for app and non-app users were not significant. Feedback revealed that approximately 60% of respondents preferred the physical modeling kit, citing ease of visualization and hands-on interactivity as its key strengths. Improvements for future work were proposed in light of the results and limitations. © Published 2022 by American Chemical Society and Division of Chemical Education, Inc.

Remedies to Avoid Failure Mechanisms of Lithium-Metal Anode in Li-Ion Batteries

Rechargeable lithium-metal batteries (LMBs), which have high power and energy density, are very attractive to solve the intermittence problem of the energy supplied either by wind mills or solar plants or to power electric vehicles. However, two failure modes limit the commercial use of LMBs, i.e., dendrite growth at the surface of Li metal and side reactions with the electrolyte. Substantial research is being accomplished to mitigate these drawbacks. This article reviews the different strategies for fabricating safe LMBs, aiming to outperform lithium-ion batteries (LIBs). They include modification of the electrolyte (salt and solvents) to obtain a highly conductive solid–electrolyte interphase (SEI) layer, protection of the Li anode by in situ and ex situ coatings, use of three-dimensional porous skeletons, and anchoring Li on 3D current collectors.

ReI Tricarbonyl Complexes as Coordinate Covalent Inhibitors for the SARS-CoV-2 Main Cysteine Protease.

Since its outbreak, the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has impacted the quality of life and cost hundreds-of-thousands of lives worldwide. Based on its global spread and mortality, there is an urgent need for novel treatments which can combat this disease. To date, the 3-chymotrypsin-like protease (3CLpro ), which is also known as the main protease, is considered among the most important pharmacological targets. The vast majority of investigated 3CLpro inhibitors are organic, non-covalent binders. Herein, the use of inorganic, coordinate covalent binders is proposed that can attenuate the activity of the protease. ReI tricarbonyl complexes were identified that demonstrate coordinate covalent enzymatic inhibition of 3CLpro . Preliminary studies indicate the selective inhibition of 3CLpro over several human proteases. This study presents the first example of metal complexes as inhibitors for the 3CLpro cysteine protease.